title: Expression and significance of HMGB1, TLR4 and NF-κB p65 in human epidermal tumors.
abstract: BACKGROUND
  High mobility group protein box 1 (HMGB1) is a DNA binding protein located in nucleus. It is released into extracellular fluid where it acts as a novel proinflammatory cytokine which interacts with Toll like receptor 4 (TLR4) to activate nuclear factor-κB (NF-κB). This sequence of events is involved in tumor growth and progression. However, the effects of HMGB1, TLR4 and NF-κB on epidermal tumors remain unclear.
  
  
  METHODS
  Human epidermal tumor specimens were obtained from 96 patients. Immunohistochemistry was used to detect expression of HMGB1, TLR4 and NF-κB p65 in human epidermal tumor and normal skin specimens. Western blot analysis was used to detect the expression of NF-κB p65 in epithelial cell nuclei in human epidermal tumor and normal tissues.
  
  
  RESULTS
  Immunohistochemistry and western blot analysis indicated a progressive but statistically significant increase in p65 expression in epithelial nuclei in benign seborrheic keratosis (SK), precancerous lesions (PCL), low malignancy basal cell carcinoma (BCC) and high malignancy squamous cell carcinoma (SCC) (P <0.01). The level of extracellular HMGB1 in SK was significantly higher than in normal skin (NS) (P <0.01), and was higher than in SCC but without statistical significance. The level of TLR4 on epithelial membranes of SCC cells was significantly higher than in SK, PCL, BCC and NS (P <0.01). There was a significant positive correlation between p65 expression in the epithelial nuclei and TLR4 expression on the epithelial cell membranes (r = 0.3212, P <0.01).
  
  
  CONCLUSIONS
  These findings indicate that inflammation is intensified in parallel with increasing malignancy. They also indicate that the TLR4 signaling pathway, rather than HMGB1, may be the principal mediator of inflammation in high-grade malignant epidermal tumors. Combined detection of p65 in the epithelial nuclei and TLR4 on the epithelial membranes may assist the accurate diagnosis of malignant epidermal tumors.
authors.affiliation: Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Weng
authors.forename: Yunhua
authors.initials: Y
authors.lastname: Deng
authors.forename: Yuyan
authors.initials: Y
authors.lastname: Xie
authors.forename: Hongbo
authors.initials: H
authors.lastname: Liu
authors.forename: Feili
authors.initials: F
authors.lastname: Gong
mesh_terms: D000704:Analysis of Variance; D002280:Basal Cell Carcinoma / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D005110:Extracellular Space / Q000378:metabolism; D024243:HMGB1 Protein / Q000378:metabolism*; D006801:Humans; D017492:Keratosis, Seborrheic / Q000378:metabolism; D011230:Precancerous Conditions / Q000378:metabolism*; D015398:Signal Transduction; D012867:Skin / Q000378:metabolism; D012878:Skin Neoplasms / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D051996:Transcription Factor RelA / Q000378:metabolism*
chemical_list: D024243:HMGB1 Protein; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D051996:Transcription Factor RelA